Handle good things like:
```ruby
url "https://example.org/download",
verified: "example.org/download" # This is fine.
```
And bad things like:
```ruby
url "https://example.org/",
verified: "example.org" # This should end with a slash.
```
- Apparently the "verified" parameter in the URL (present when a Cask's
download URL is not the same as its homepage) shouldn't have the
protocol (`https`, `http`) at the front.
- Removing this has happened manually in the past, so here's an
autocorrecting RuboCop for it.